Copyright (c) 2000, 2005 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.text.projection;


import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextStore;
import org.eclipse.jface.text.Region;


A text store representing the projection defined by the given document
information mapping.
Since:
3.0/**
 * A text store representing the projection defined by the given document
 * information mapping.
 *
 * @since 3.0
 */
class ProjectionTextStore implements ITextStore {

	
Implementation of IRegion that can be reused by setting the offset and the length. /**
	 * Implementation of {@link IRegion} that can be reused
	 * by setting the offset and the length.
	 */
	private static class ReusableRegion implements IRegion {

		private int fOffset;
		private int fLength;

		@Override
		public int getLength() {
			return fLength;
		}

		@Override
		public int getOffset() {
			return fOffset;
		}

		
Updates this region.
Params:
offset – the new offset
length – the new length/**
		 * Updates this region.
		 *
		 * @param offset the new offset
		 * @param length the new length
		 */
		public void update(int offset, int length) {
			fOffset= offset;
			fLength= length;
		}
	}

	
The master document /** The master document */
	private IDocument fMasterDocument;
	
The document information mapping /** The document information mapping */
	private IMinimalMapping fMapping;
	
Internal region used for querying the mapping. /** Internal region used for querying the mapping. */
	private ReusableRegion fReusableRegion= new ReusableRegion();


	
Creates a new projection text store for the given master document and
the given document information mapping.
Params:
masterDocument – the master document
mapping – the document information mapping/**
	 * Creates a new projection text store for the given master document and
	 * the given document information mapping.
	 *
	 * @param masterDocument the master document
	 * @param mapping the document information mapping
	 */
	public ProjectionTextStore(IDocument masterDocument, IMinimalMapping mapping) {
		fMasterDocument= masterDocument;
		fMapping= mapping;
	}

	private void internalError() {
		throw new IllegalStateException();
	}

	@Override
	public void set(String contents) {

		IRegion masterRegion= fMapping.getCoverage();
		if (masterRegion == null)
			internalError();

		try {
			fMasterDocument.replace(masterRegion.getOffset(), masterRegion.getLength(), contents);
		} catch (BadLocationException e) {
			internalError();
		}
	}

	@Override
	public void replace(int offset, int length, String text) {
		fReusableRegion.update(offset, length);
		try {
			IRegion masterRegion= fMapping.toOriginRegion(fReusableRegion);
			fMasterDocument.replace(masterRegion.getOffset(), masterRegion.getLength(), text);
		} catch (BadLocationException e) {
			internalError();
		}
	}

	@Override
	public int getLength() {
		return fMapping.getImageLength();
	}

	@Override
	public char get(int offset) {
		try {
			int originOffset= fMapping.toOriginOffset(offset);
			return fMasterDocument.getChar(originOffset);
		} catch (BadLocationException e) {
			internalError();
		}

		// unreachable
		return (char) 0;
	}

	@Override
	public String get(int offset, int length) {
		try {
			IRegion[] fragments= fMapping.toExactOriginRegions(new Region(offset, length));
			StringBuilder buffer= new StringBuilder();
			for (IRegion fragment : fragments) {
				buffer.append(fMasterDocument.get(fragment.getOffset(), fragment.getLength()));
			}
			return buffer.toString();
		} catch (BadLocationException e) {
			internalError();
		}

		// unreachable
		return null;
	}
}